Fog is a particular meteorological status of air with a high degree of humidity, an almost total absence of wind and with a condition of thermic inversion being near 0.degree. C. near ground level, with consequential crystallization of water micro-droplets. Under these conditions, the fog phenomenon is produced and visibility is severely reduced. Fog conditions are especially hazardous on vias such as roadways and airport runways. They are also objectionable in closed densely populated buildings such as sports arenas.
By eliminating one or another of the above factors, the fog phenomenon may be interrupted and the quickest and most economically convenient way to do this is to replace humid air with "dry" air in the effected air space.